This invention relates generally to rapid prototyping processes, and more particularly to an infiltrant system to be used for a part made by a rapid prototyping process, and a method for applying the infiltrant system to a part.
The conventional machining of prototype parts or production of cast or molded parts by hard or soft tooling techniques can take weeks and even months depending on the complexity of the part. It is an expensive and time-consuming process, and if changes need to be made, the mold may be useless.
Rapid prototyping was developed so that prototype parts could be made quickly, easily, and less expensively. There are two basic methods of rapid prototyping: a selective laser sintering process and liquid binder three dimensional printing process. Both use a layering technique to build a three-dimensional article. Thin cross-sections of the article are formed in successive layers. The particles in the layer are bonded together at the same time the cross-sectional layers are bonded together. Both processes allow parts to be made directly from computer-generated design data, and the parts can have complex cross-sections.
In selective laser sintering, a thin layer of powdered material is spread on a flat surface with a counter-roller. A laser is applied to the layer of powdered material in a predetermined pattern. The laser fuses the powder together. Additional layers of powdered material are applied and fused with the laser.
In the liquid binder three dimensional printing process, a layer of powdered material is applied to a surface with a counter-roller. A liquid or colloidal binder is applied to the layer of powder with an ink-jet printhead. The binder coats the powder and hardens, bonding the powder in that layer together and bonding the layers together. The process is repeated until the desired shape is obtained. When the part is taken out of the printer, it is fragile, and it does not have much cohesive strength. The part has to be reinforced and strengthened with an infiltrant system in order to make it functional. The infiltrant may fill in any pores in the part, improving the surface finish, and making it more impervious to water and other solvents. Known infiltrant materials include wax, varnish, lacquer, cyanoacrylate, polyurethane, and epoxy. The infiltrated part can then be used to assess the performance of the design.
Still, there is a need for improved infiltrant systems for rapid prototyping processes.